Current hearing aid fitting methods and instrumentations are generally costly and too complex for use by consumers and non-expert operators. The methods generally require administration by a hearing professional in a clinical setting. For example an audiometer is typically required to produce an audiogram report, which forms the basis of hearing assessment and prescriptions in conventional fitting methods. Other instruments used may include a hearing aid analyzer, and a real-ear measurement (REM) instrument. A specialized sound-proof room, sometimes referred to as a sound room, is also generally required for conducting part or all of the fitting process. The fitting prescription from an audiogram report may be determined from a generic fitting formula, such as NAL or POGO, or from a proprietary formula, generally provided by the manufacturer of the hearing aid being fitted. The computations for the prescription are generally limited to hearing professional use, and the resultant prescriptions may vary considerably depending on the formula used, sometimes by as much as 20 decibels due to various factors including personal preferences.
Characterization and verification of a hearing aid prescription are generally conducted by presenting test sounds to the microphone of the hearing device, referred to herein generally as a microphonic or acoustic input. The hearing aid may be worn in the ear during the fitting process, for what is referred to as “real ear” measurements. Or it may be placed in a test chamber for characterization by a hearing aid analyzer. The stimulus used for testing is typically tonal sound but may be a speech spectrum noise or other speech-like signal such as “digital speech.” Natural or real-life sounds are generally not employed in determination of a hearing aid prescription. Hearing aid users are generally asked to return to the clinic following real-life listening experiences to make the necessary adjustments. If real-life sounds are used in a clinical setting, a calibration procedure involving probe tube measurements with REM instruments is generally required. Regardless of the particular method used, conventional fittings generally require clinical settings to employ specialized instruments for administration by trained hearing professionals. The term “hearing aid,” used herein, refers to all types of hearing enhancement devices, including medical devices prescribed for the hearing impaired, and personal sound amplification products (PSAP) generally not requiring a prescription or a medical waiver. The device type or “style” may be any of invisible in the canal (IIC), in-the-canal (ITC), in the ear (ITE), a receiver in the canal (RIC), or behind the ear (BTE). A canal hearing device refers herein to any device partially or fully inserted in the ear canal.
Programmable hearing aids generally rely on adjustments of the electroacoustic settings programmed within, referred to herein generally as “fitting parameters”. Similar to hearing assessments and hearing aid prescriptions, the programming of a hearing aid generally requires specialized programming instruments and the intervention of a hearing professional to deal with complexities related to fitting parameters and programming thereof, particularly for an advanced programmable hearing aid, which may comprise over 15 adjustable parameters, and in some cases over 50 parameters.
For the aforementioned reasons among others, the fitting process for a programmable hearing device is generally not self-administered by the consumer. Instead, a licensed dispensing professional is typically involved for conducting at least one part of the fitting process, which may include hearing evaluation, hearing aid recommendation and selection, fitting prescription, fitting parameter adjustments and programming into the hearing device. This process often requires multiple visits to a dispensing office to incorporate the user's subjective listening experience after the initial fitting. Conventional fitting processes are generally too technical and cumbersome for self-administration, or for administration by a non-expert person. As a result, the cost of a professionally dispensed hearing aid, including clinician effort and the specialized instruments used in clinical settings, can easily reach thousands of dollars, and that cost is almost double for a pair of hearing aids. The high cost of hearing devices thus remains a major barrier preventing many potential consumers from acquiring a hearing aid, which typically costs under $100 to manufacture.